As American and Middle East leaders begin peace talks in Washington, public discussion in the weeks ahead will likely center on borders, security, settlements and the fate of Jerusalem. But behind all of this, in the negotiators' minds a threat hangs like the sword of Damocles: Isn't the Palestinian population growing so fast that, soon enough, they will outnumber Jews in the land between the Jordan River and Mediterranean Sea?

American presidents and Israeli prime ministers have been issuing dire warnings about this for years. Late last year, former President Bill Clinton, speaking in Jerusalem, chastised Israelis, saying: "Two things remain unchanged" since he was president, "geography and demographics. Palestinians have more children than Israelis have or can import."

Former Israeli Prime Minister Ehud Olmert, speaking to Israel's parliament in 2007, predicted "a demographic battle, drowned in blood and tears" if Israel did not settle with the Palestinians.

These stark warnings generally come from the Israeli left, which favors trading land for peace. Give the Palestinians their own state on the West Bank, they say, and the demographic nightmare will disappear. The Palestinians can have all the babies they want, and they will be residents of Palestine, not Israeli-occupied territory.

But they may all be wrong. A team of demographers headed by Yoram Ettinger, a former Israeli diplomat, conducted a detailed study and found to most everyone's surprise that, in fact, Israeli Jews far out number Palestinians and Israeli Arabs. What's more, Jewish birth rates are higher now, too. The demographic threat, these demographers say, simply doesn't exist.

But then, of course, as always happens in Israel, the new study became simply a political football. For advocates of territorial compromise, the population threats were a convenient tool. Not long ago, Meron Benvenisti, an iconoclastic Israeli leftist, warned that "the democratic revolution -- the Arabs becoming a majority in the area west of the Jordan River -- will happen in a year or two."

Earlier this year, Martin Kramer, a prominent right-wing American academic who writes a blog on the Middle East, urged the West to stop "providing pro-natal subsidies for Palestinians with refugee status. Those subsidies are one reason why, in the ten years from 1997 to 2007, Gaza's population grew by an astonishing 40 percent." Palestinians accused him of advocating genocide.

Among the critics of Ettinger's study, a prominent left-wing academic, Arnon Sofer of Haifa University, called it a politically inspired illusion. Well, I know Yoram Ettinger, and I find his work convincing.

Palestinians vastly overstated their population, for their own political aims. As examples, they double-counted Arab residents of East Jerusalem and included about 400,000 Palestinians who actually live abroad. At the same time, as the West Bank grows more modern and prosperous, Palestinian birth rates are falling -- while some zealot Israeli West Bank settlers are having as many babies as they can, trying to establish demographic facts on the ground.

All told, Ettinger's study found, 60 percent of the people who live in Israel, the West Bank and Gaza are Israeli Jews, and the trend lines favor the Jews, not the Arabs.

What does all of this mean for the peace talks? Ettinger told me the new research "spares us a supposed demographic calamity" and, he hopes, will "set negotiations on a realistic foundation."

In truth, how much does this really matter? The unending Israeli demographic arguments remind me of the immigration debate in the U.S., each side grabbing the statistic or anecdote that best serves his point of view while ignoring the countervailing facts. And even if Palestinians did outnumber Jews in the land west of the Jordan River, would it make that much practical difference -- as long as the West Bank remains occupied territory, not part of Israel, while Gazans live in an independent territory/prison?

But if the new data does win broad acceptance, it may serve one purpose at the peace talks that the researchers never intended. The Palestinian platform for a political settlement calls for the right of return for Palestinians who lost their homes in Israel when the state was founded in 1948. (Actually, now it would be their grandchildren.)

Israel has always insisted it would never accept that; admitting thousands of new Arab residents would irrevocably alter Israel's demographics and leave Jews without a majority. But if Ettinger's data is correct, that's all wrong. Israel could let those Palestinian families back in, and the Jews would face no demographic threat, which just goes to show: In the Middle East, be careful what you wish for.

Joel Brinkley, a professor of journalism at Stanford University, is a former Pulitzer Prize-winning
foreign correspondent for the New York Times.)